Apparatus for obtaining aerosols



y 29, 1952 DAUTREBANDE 2,605,089

APPARATUS FOR OBTAINING AEROSOLS Filed July 2'7, 1948 FIGJ. -8

| l 3 4 55- 5- 5-2 5! 5% 32-3-52- 11*; Z i 5 INVENTOR. LUCIEN DAUTREBANDE HIS ATTORNEYS.

the therapeutic agenti,

Patented July 29, 1952 APPARATUSZFOR OBTAINING AEROSOLS LuciemDautrebande; Washington; assignor of. Aerosol Corporation 01- America; NBW.Y l'k;.

N. ,Yi,a corporation of Delaware 't Applicationtlulyfl'l, 1948; S eria'l No.4 0,9f48' EClaiinsi (01-. 261-78) I This inventicn-relatesto apparatus for obtaining improved/aerosols; ofv relatively high stability by obligatoryafiltr-ation :through-- a turbulent body of liquid; and especially; to aerosols havihg-- a mean partiolersize 0r diameter of-notover about otrm r V ,In aerosol therapmzit is: very important to obtain aerosols of: very low particle size. it. it is desired to-: have the aerosol-penetrate to the innermostjpassagesior zones; in! .thelungs- (alveoli) For thispurpose aerosolssof not oven 0.5 micron mean particle. size are tof be. preferred, and in general the aerosols-should besubstantially free of particles of more than L'micron. diameter.

The larger aerosol particles attract "the-smaller ones,- they tend to.- deposit in .the nasal and throat passages and in'some. instances such deposit leads to serious} diilieulties or to a lack. of effectiveness 'of the lsubstances dispersed;

In accordance withthe invention, it .has. been found that aerosols zoff-almeanparticle size. of not over 0.5 micronmay. beobtainedf readily. by meansof aconvenient apparatus..

Oneof theobject's, ofsthe. invention is to mdu'ce improved... aerosols...having; amean'Q particle size oiv not. over 0'.5i'.micr'on.. Another object of the invention isthe provision Iof apparatus 'for obtaining improved! aerosols.v Other. objects of the invention will. bexabllfl itent. as details or embodiments of the invention are 'set forth; hereinafter.

y In. accordance .witlitfie nvention; aQliqu'id is dispersedlb'y. means .of"a'..'coiii'p'ressed "gas, such .as

mean particle size ornbtmert DIE-micron e. g.,

using anair. inltipresshr. in merange. of to 55 pounds.- per square incli gaugglan aqueeus solution. of .a solute in..usuallconcentration suitable for aerosoltherapy e; g..,.',10l%i by. weight 0f Referring, to. the; drawing; gu re. l 'diagram matically illustrates fanapparatus; suitable for carrying out the method of the invention-,parw

a .liciuid reservoir ;detachab-l-y connected e. g.,. byscrew threads-5;.for holding the liquid to be: dispersed a jetmember made up of air inlet 3 and'liquid'supply tube lwhichextends into the liquid to be dispersed. A somewhat S-shaped taperedtubular aerosol conduit member 6- is provideddirectly-over the aerosol ,sggenerating zone: 2, This' memberhas-onesrelatively gradual 90? to 150Icurye i zone A, and,

toward the outlet end therefrom; two relatively sharp-about 9 0 curved zones; B andC lt may have a curved-zone X neartheinlet end; below and curved in the opposite: direction; to zoneA.

. The; loweror laineireuend-of-v member 6 is1pref.

erabl-y-twice the diameter of; the upperor smaller end-thereof; and the-len th is: 1 5' to 25 timestthis smaller" diameter-y The lower" or aerosol. inlet section of member 6 is set substantially "yertically, whereas the llD-PGIZOR aerosolloutl'etfsec- ,tion of member 6- is set.substjantiallyfhorizontally. If 1 desired, a fine screenimeinbei-I 6'. may: be -set across the outlet end of members 61" The bog-lilge l caili e member Q' hascIoSedi back, side and; top members and a artially closed front member, Itis set-withit's Ibackmember. at (right angle to the axi s ot theiuppersection of member 6. This is illustrated in.'perspectiife'in Figure 2. k aerosoloutlet 8 is providedlatithe top o eel-fl- I a 7. If desired the liquid. reservoir inivesseli. I may haveaconical shaped bottom or b'e fproilided with a suitable. feedingideilioe for maintaining constantlevel of dicruid therein, or'itIi'iia'y be rovided with .means ior continuallyfrefliovihg liquid therefrom and replacing it .with solution i of 'controlled concentrations If desire "'{ItHeIliQui-d'tO be dispersed- InayJ fe'd.. under 7 I it'mosphene": or P Ve: pressure directly into tube-54;. e. g1, frorn sui able connections I H v I concentration offthe solute during" the dispersionjprocess},

In operation, compressedv air or vother suitable gas-is introduced intotube 3;. unde-r such conditions' 1 that liquid wil be drawn-up still-011g h: 4 tube 4- and dispersed in the iorm of a-cloud or a mist at zone 2-and impelled upwardly into the vIncinber 6.- The-relati ge airiandliquidfl are-suchthat the v w contains a asubstantial amount of --unstable liquid particles, which fCOfi/IBSfZfiQQdffOiIXI ayery turbu lent liquid may lathe mb r. 6-,- especial the;gradually;.;curved zone A; Thisliqui ody i mai t ined: in.- dy iam c: e u libri -i. a by balan in the; a oun o li u dp ied thereto against ,thesan ount, running; downward therefrom: i; In this 1 turbulent liquid body; the

' is directed against the inner side of the back of the box-like baflle member 9, and must make at least one right angle change of direction in passing from baflie member 9 to the aerosol exit 8.

The existence and maintenance of the turbulent liquid body is of great importance in carrying out my invention as disclosed herein. I have found that the formation and utilization of the 4 of larger relatively unstable particles. The unstable particles vvill tend to be removed in the turbulent liquid body or in the treatments subsequent to contact with the turbulent body, or both.

The relatively uniform aerosols of very low mean particlesize, havingsub'starrtially all particles'of less than 1 micron'ma'xiinum size, are particularly suitable for" use in aerosol therapy, particularly in the treatment of the innermost passages or regions (alveoli) in the lungs. If

' it is desired to simultaneously treat or medicate one or more turbulent liquid masses is critical 7 in the production of aerosol of the preferred small size and uniformity. This may be due to the myriad of liquid filmscomprising the turbulent mass which are available to act upon the aerosols as they pass through the zones A, B and C.

The jet member may have one, two or three sets of air and liquid apertures, three being present in the one illustrated in the drawing, arranged so as to direct the cloud or mist into the lower end of member 6.

In general, the size of theapertures is preferably such as to deliver a rate of air flow per aperture in the range of 15 to liters per minute, for conventional relatively low air pressures of the order of 7 to 55 pounds per square inch gauge. For such an air flow, the rate of dispersion of liquid is preferably in the range of 10 to'20 cc. per hour.

In a typical example, a 10% aqueous solution of eosins is dispersed as aerosols of a mean particle size of about 0.4 micron, using the apparatus of Figure 1, with an air input of 28 pounds per square'inch gauge. The particle size of the aerosols is determined bypassing the aerosols into a chamber, e. g., of 225 cubic meters capacity, the interior of which is maintained at atmospheric pressure. After dispersion for lo minutes, the aerosols are allowed to settle on collector plates, coated with a thin film of petrolatum, e. g., for an hour, then the plates are protected by a cover, cemented at the edges, e. g., with a quick drying pyroxylin base cement, obtainable commercially under the trade name Duco cement, and

immediately examined by means of an oil immersion microscope, e. g., 1125 magnification.

Alternatively, the particle size may be determined by nephelometric methods or by electron micros'cope means. In the latter method, there are observed aerosol particles which are too small to be seen by meansof the optical microscope, and when these are taken into consideration, the mean particle size of the aerosol will be even smaller (about 0.09 micron, mean size, as determined after collecting, freezing and drying).

The apparatus or parts thereof may be made of glass, metal," plastic, "or the like suitable material; and although various members are described as being substantially circular in cross section, other shapes may be used provided the critical relationships disclosed are retained.

The particular jet members discussed above are admirably adapted I for producing aerosols. However,"other typesof jet members may be used, as known in the art, provided the resulting mist or cloud contains'both very fine liquid particles and also a substantialamount the nasal or throat passages, larger mean particle size aerosols, having some particles of the order of 1 to 5 microns diameter, may be used.

The aerosols produced in accordance with the invention may, be suitable for other uses, e. g., precipitation or agglutination of very fine dust particles, which dust particles are so fine that they pass through a liquid layer, through the nasal and throat passages,- and into the innermost regions of the lungs where they may deposit and produce very undesirable effects, e. g., silicosis. The very fine aerosol particles tend to agglomerate and coalesce with the very fine dust particles, to produce larger size individual particles and to' produce "dust aggregates which settle down more quickly-and do not penetrate further than the upper respiratory passages.

Inview of the foregoing disclosures, variations and modifications thereof will be apparent to those skilled in the art, and all such variations and modifications are broadly contemplated within the invention."

1. In an apparatus for-producing an improved aerosol, avessel provided'with'atomizin'g means comprising a liquid feed-tube and an air inlet tube, a tapered tubular conduit member having its larger end set' axiallysubstantially over said atomizingmeans;-said conduit'member having at least one gradual to about curved zone and at least two sharp about 90 curved zones above said gradual curved zone, the smaller end of said conduit member being axially substantially horizontal, and a box-like baffle member surrounding said smaller end of said conduit memher, said bafile being closedat the back, top, sides and at aboutthe upperOne-third of thefront side relative to said "conduit member, and an aerosol outlet tube from said vessel.

2. In an apparatus for producing an improved aerosol, a vessel provided with atomizing means comprising a liquid feed tube'in communication with alliquid supply and'an air'inlet tube, a tapered tubular conduit member having its larger end set axially substantially vertically over said atomizing means, said conduit'member having at least one gradual90 to about l50fcurved zone and at least two sharp about 90 Cu ved zones above saidgradual curved zone, the'smaller end of said conduitmember being axially s'ubstantially horizontal, a fine meshed 'screenacross said smaller end of said conduit member, "and a boxlike bafiie member surrounding said smaller end of said conduit member; saidbafile being closed at the back, top, sides and at about the'upper onethird of the front side' relative to" said conduit member, and aerosolputlet tube from said vessel.

atomizing means comprising "a liquid feed tube in communication with-the said reservoirand an air inlet tube,-a tapered tubular" conduit member having its larger end set axially substantially vertically over said atomizing means, said conduit member having at least one gradual 90 to about 150 curved zone and at least two sharp about 90 curved zones above said gradual curved zone, the smaller end of said conduit member being axially substantially horizontal, and a boxlike baflle member surrounding said smaller end of said conduit member, said bafile being closed at the back, top, sides and at about the upper onethird of the front side relative to said conduitmember, said smaller end of said conduit member being set near the middle of the back of said boxlike bafile member, and an aerosol outlet tube from said vessel.

4. In an apparatus for producing an improved aerosol, a vessel provided with a liquid reservoir, atomizing means comprising a liquid feed tube in communication with the said reservoir and an air inlet tube, a tapered tubular conduit member having its larger end set axially substantially vertically over said atomizing means, said conduit member having at least one gradual 90 to about 150 curved zone and at least two sharp about 90 curved zones above said gradual curved zone, the smaller end of said conduit member being axially substantially horizontal, the larger end of said condit member being twice the diameter of the smaller end, and a box-like baffle member surrounding said smaller end of said conduit member, said baffle being closed at the back, top, sides and at about the upper one-third of the front side relative to said conduit member, said smaller end of said conduit member being set near the middle of the back of said box-like bafile member, and an aerosol outlet tube from said vessel.

5. In an apparatus for producing an improved aerosol, a vessel provided with a liquid reservoir, atomizing means comprising a liquid feed tube in communication with the said reservoir and an air inlet tube, a tapered tubular conduit member having its larger end set axially substantially vertically over said atomizing means, a hood member set around and over said conduit member, said hood member having a closed top and apertured sidewalls and said hood member dividing said vessel into two zones, said conduit member having at least one gradual to about curved zone and at least two sharp about 90 curved zones above said gradual curved zone, the smaller end of said conduit member being axially substantially horizontal, the larger end of said conduit member being twice the diameter of the smaller end, and a box-like bafile member surrounding said smaller end ofsaid conduit member, said baflie being closed at the back, top, sides and at about the upper one-third of the front side relative to said conduit member, said smaller end of said conduit member being set near the middle of the back of said box-like bafile member, and an aerosol outlet tube from said vessel.

LUCIEN DAUTREBANDE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 740,714 Titus et a1 Oct. 6, 1903 1,640,564 Burdick Aug. 30, 1927 2,330,297 Lynch Sept. 28, 1943 2,382,681 Trier Aug. 14, 1945 2,400,179 Venable May 14, 1946 

